Helo command rejected: Host not found;

[Josef Sturm]

An Australian Government site is trying to send me a (confirmation) email, but my mail server (set up and run by myself) rejects the incoming email.

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Nov 8 05:26:24 mail1 postfix/postscreen[1685596]: CONNECT from [103.151.87.18]:60820 to [xxx.xxx.xxx.xxx]:25
Nov 8 05:26:24 mail1 postfix/postscreen[1685596]: PASS OLD [103.151.87.18]:60820
Nov 8 05:26:28 mail1 postfix/smtpd[1685599]: connect from s2bulkseg.ato.gov.au[103.151.87.18]
Nov 8 05:26:31 mail1 postfix/smtpd[1685599]: NOQUEUE: reject: RCPT from s2bulkseg.ato.gov.au[103.151.87.18]: 450 4.7.1 <s2-smtp-ato-esa32.secureintellicentre.net.au>: Helo command rejected: Host not found; from=<nor...@mygovid.gov.au> to=<l...@xxx.com> proto=ESMTP helo=<s2-smtp-ato-esa32.secureintellicentre.net.au>
Nov 8 05:26:36 mail1 postfix/smtpd[1685599]: disconnect from s2bulkseg.ato.gov.au[103.151.87.18] ehlo=2 starttls=1 mail=1 rcpt=0/1 rset=1 quit=1 commands=6/7
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Appreciate if somebody could tell me if this may be due to something I've set up incorrectly.
All other mails to my domain come through
Thanks

[Bob Nichols]

There is no DNS "A" record set up for the hostname
"s2-smtp-ato-esa32.secureintellicentre.net.au", reported in the
HELO/EHLO command from the sending server. Such a message would
be deferred in this way if "smtpd_helo_restrictions" includes
"reject_unknown_helo_hostname".

If that is not the case, please post your main.cf configuration.
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